1. Technical Field
The present invention relates to a rotary switch for vehicles having a plurality of rotational positions for operating a plurality of different lighting groups and several spring-loaded axial positions for operating several different lighting groups, as well as a method for controlling electronic functions in vehicles utilizing such a switch.
2. Background Art
In modern vehicles there are many functions that are controlled electronically. Some of these functions are of the on/off type and require no other control than a simple switch, for example certain light functions. Some functions, however, can be switched to several positions, for example windscreen wipers. The control of these functions is carried out using some form of switch with several positions. A switch can either be a full-load switch, where the load is connected directly to the switch, or a low-level switch, where the load is connected to a power unit, for example a relay, which is controlled by the switch.
A problem with having many electronic functions and hence many switches, is that the location of the switches can easily become confusing. Another problem is that the switches should be located within easy reach of the driver. This can be a disadvantage, particularly in trucks and busses that usually have many more switches than automobiles. In addition, for the sake of driver clarity, it is desirable to have all the switches that control the same type of function collected in a defined group.
A common way of limiting the number of switches is to use multi-function switches or multi-function modules; for example, all light functions on a vehicle can be controlled by one switch or by a module in which the switches for controlling the light functions are integrated.
A rotary switch that is known to the skilled person in the field has three rotational positions; the first position denoting switched-off lights, the second position denoting parking lights and the third position denoting full/dipped beam of the headlamps. In addition, this switch has two pulled-out positions for fog lamps, by which the front and rear fog lamps are controlled. The pulled-out positions are controlled mechanically in such a way that the fog lamps can only be activated in the third rotational position. When the rotary switch is turned towards the first position, the fog lamps are deactivated.
A disadvantage of this type of switch is that it is expensive and complicated to achieve the mechanical control for the pulled-out positions. In addition, several different versions of the switch are required to cover the different combinations of possible functions that are required. Another disadvantage is that front and rear fog lamps cannot be controlled individually. A further disadvantage is that the pulled-out positions of the switch are not reset automatically when the vehicle's engine is switched off. Depending upon how the fog lamp function is implemented, this can mean that the driver can inadvertently leave the fog lamps switched on or that the driver can believe that the fog lamps are activated when they are actually switched off. In addition, there can be legal requirements for the fog lamp function to be deactivated when the vehicle's engine is started up.
Similar rotary light switches with one or more pulled-out positions are described in, for example, WO 00/48215, U.S. Pat. Nos. 5,546,067, 4,164,633, 5,491,311, 4,885,434 and EP 0342031.
Another rotary switch that is known to experts in the field has a similar function with rotational positions and two pulled-out positions for fog lamps. This switch has an electromagnet that holds fast a spring-loaded control element in the pulled-out positions of the switch. When the vehicle's engine is switched off or when the rotary switch is turned towards the zero position, the electromagnet releases the control element that returns to its normal position.
Disadvantages of this switch are that it is expensive and complicated. Several different versions of the switch are also required for this switch to cover the different combinations of possible functions that are required. Another disadvantage is that front and rear fog lamps cannot be controlled individually.
A third way of solving the problem of lack of space and clarity is to arrange a rotary switch with a number of two-way switches in a module. Examples of this solution are described in, for example, U.S. Pat. Nos. 5,773,935, 5,736,696, 6,034,337 and 5,281,779.